1. Field
The field relates to an organic light emitting display device and a method of driving the same, and more particularly to an organic light emitting display device having uniform luminance characteristics regardless of the driving frequency, and a method of driving the same.
2. Description of the Related Technology
In recent years, various flat panel displays have been developed which are light-weight and small-sized when compared with cathode ray tubes. Particularly, an organic light emitting display device has become popular because the organic light emitting display device has excellent luminance and color purity. The organic light emitting display uses an organic compound as a light emitting material.
An organic light emitting display device is thin, light-weight and driven at a low power consumption, and therefore it is expected that the organic light emitting display device may be widely used in the field of various display devices.
However, the organic light emitting display device may display images with different luminances despite receiving the same data signal. The luminance can depend on the time that a data signal is supplied to (or charged in) the pixels.
For example, when the organic light emitting display device is driven using an NTSC (National Television Systems Committee) signal having a driving frequency of 60 Hz, the time that each data signal is supplied to the pixels is less than that when the organic light emitting display device is driven using a PAL (Phase Alternation by Line) signal having a driving frequency of 50 Hz. This results in the overall deterioration in the luminance of images.
In particular, in the case of the organic light emitting display device having no frame memory in a drive IC, a data signal may be output from a drive circuit unit to the pixels since the data signal is synchronized with a synchronizing signal corresponding to the driving frequency. Therefore, the time that a data signal is supplied to the pixels varies according to the driving frequency.
That is to say, when the same organic light emitting display devices are driven with drive modes having different driving frequencies, the luminance varies according to driving frequency.
Also, when a separate drive circuit unit is used for each driving frequency to realize uniformity of luminance across the drive modes, the manufacturing cost is high and the manufacturing efficiency is low.
Therefore, there is an increasing demand for an organic light emitting display device and a method of driving the same that may apply to various drive modes having different driving frequencies so as to display an image with uniform luminance regardless of the driving frequencies.